UPL was established in 1996, following the de-regulation of the utility industries, with the aim of helping customers find the best available deals across the gas, electricity, telecommunications and water markets.

It has toped the latestDeloitte poll after recording annual growth in excess of 1,764% over the last three years.

Nine other South Wales-based technology companies made it into top 50 list:

Comtec Europe, Cwmbran (3rd place);

Fusion, Newport (6th);

Gyrus, Cardiff (11th);

Penn Pharmaceutical Services, Tredegar (17th);

Fifth Dimension Systems, Cardiff (18th);

Birchfield Interactive, Cardiff (22nd);

Biomet Merck, Bridgend (36th);

Glamorgan Telecom, Cardiff (43rd);

Target, Cardiff (49th).

John Foster Thomas, partner in charge at Deloitte in Cardiff, said, "With an extraordinarily successful growth rate over a three-year period to 2002, it is understandable why UPL topped the Deloitte Fast 50 table.

"Last year the company was ranked seventh in the table. In addition to this, I am delighted that nine other South Wales companies were listed in the final 50"